The present invention relates to methods for distinguishing human solid non-lymphoid tumor cells with lymphotropic metastatic potential from those without this property and for treatment thereof.
2.1. Metastasis
Metastasis or the spread of primary tumor cells to a secondary organ is a complex process involving a cascade of steps (Paget, S., 1889, Lancet, 1:571-573, Fidler, I. J., 1990, Cancer Res. 50:6130-6138). Neoplastic transformation usually results in the dedifferentiation of pre-malignant cells. Consequently, there is a loss of cell-to-cell adhesiveness and a detachment of tumor cells from the primary tumor bed. However, detachment does not ensure the spread of primary tumor cells to distant sites, since tumor cells must also acquire migratory capability to invade a secondary organ (Fidler, I. J., Kripke, M. L., 1977, Science 197:893-895.). More specifically, tumor cells must have target specific motility and preferential chemotaxis to direct them toward either blood vessels (hematogenous metastasis) or lymphatics (lymphotropic metastasis) (Willis, R A. 1972. 3rd Edit. London: Butterworth). It is our hypothesis that primary tumor cells may become metastatic by acquiring the phenotypic properties of migrating T lymphocytes. Once they acquire this invasive phenotype, these T cell xe2x80x9clikexe2x80x9d solid tumor cells can either be swiftly carried away by blood flow or may roll through lymphatic channels (Imhof, B. A., Dunon, D., 1995, Adv. Immunol. 58:345-416). Migration of tumor cells is promoted by specific receptor/ligand interactions between the tumor cells and cells lining the endothelium of secondary sites (Weiss et al., 1988, FASEB J. 2:12-21; McCarthy et al., 1991, Sem. Cancer Biol. 2:155-167) where arrest and adhesion of tumor cells occurs. Here the tumor cells may die, become dormant, or invade the organ""s parenchyma where they proliferate and undergo homeotypic aggregation (Yefenof et al., 1993, Proc. Natl. Acad. Sci. 90:1829-33; Cohen et al., 1995, In: NK Cells in the Liver, Bouwens L, ed. RG Landes Biomedical Publication, Austin, CRC Press. Pp. 71-100). Tumor cells use growth factors produced by the tumors themselves (autocrine) or by cells from the secondary organs (paracrine) for colony growth and survival (Radinsky, R., 1992, Cancer Metas. Rev. 12:345-361).
In accordance with this specification and claims, tumor cells may be classified as benign if they have not invaded surrounding tissue and malignant if they have done so, and malignant tumor cells may be classified as having metastatic potential if they have the capacity to spread through the lymph or blood systems to distant sites and to have non-metastatic potential if they do not have such capacity. If metastatic cells have the capacity to spread through the lymph system, they are defined herein and in the claims as having xe2x80x9clymphotropicxe2x80x9d metastatic potential. A xe2x80x9cprimaryxe2x80x9d tumor is defined, for the purpose of this specification and the claims as one which is located at its site of origin, i.e., before any metastasis thereof, as contrasted with a xe2x80x9csecondaryxe2x80x9d tumor, which is a tumor located at a site to which the primary tumor has metastasized.
Metastasis presents a cancer clinician with great difficulty in diagnosing and treating the malignant tumor because (i) metastasis may comprise as little as one or a few cells thereby evading clinical diagnosis even with modem techniques; (ii) often metastasis has already been seeded by the time a patent is diagnosed with a malignant non-lymphoid solid tumor (Silverberg et al., 1989, CA Cancer J. Clin. 39:3-21); (iii) treatment is more complex than simple surgical excision of the primary tumor; (iv) systemic therapy for metastatic non-lymphoid solid tumors, such as renal cell carcinoma (Rosenberg et al. 1985, N. Engl. J. Med. 313:1485-1492) remains ineffective with little survival advantage; and (v) not all malignant tumors have the same metastatic potential and no direct relationship has been established in determining whether any particular carcinoma will develop metastasis.
Monoclonal antibodies (Mab) have been used to characterize and classify T cell surface molecules such as the clusters of differentiation (CD) of human leukocyte antigens. As illustrated in FIG. 1, the T cell receptor (TCR), illustrated at 20, is an integral membrane protein, expressed on the surface of T lymphocytes, illustrated at 22, occurring as a disulfide linked heterodimer that is non-covalently associated with CD3 chains, illustrated at 24. TCR has been linked to autoimmune disease and anti-TCR antibodies have shown therapeutic potential for treating autoimmune disease (Basi et al., 1992, J. Immunol. Meth. 155:175-191). In some cancers, a correlation exists between an increase in concentration of the TCR associated CD8 molecule in the serum of children with non-Hodgkins lymphoma and the stage of the disease and its responsiveness to therapy (see U.S. Pat. No. 5,006,459).
Several studies have shown that T cell-associated molecules (Omar et al. 1991, AIDS5:275-281, Kawami et al., 1993, Biotherapy 6:3339; McMillan et al. 1995, lnt. J.Cancer 60:766-772) are expressed on the surface of non-lymphoid solid human tumor cells. SW620, a metastatic human colon tumor-derived from the lymph node of a 51-year-old male has been shown to possess the TCR co-receptor CD4 on its surface by several different methods including Northern analysis and FACS (Omary et al 1991. AIDS5:275-281). To date, no one has directly identified Vxcex2 sequences on the surface of carcinoma cells.
The present invention is related to our belief that the acquisition of lymphotropic metastatic potential by such transformed cells is accompanied by their ability to express aberrant lymphoid specific genes or their products including germline CTxcex2, germline Vxcex2 and their related TCR associated genes or their products and TCR associated signal transduction genes or their products. More specifically, the determination of the percentage of cells of a solid non-lymphoid tumor expressing lymphoid gene products including, but not limited to, the following three categories of closely related lymphoid specific genes or their products: Category 1, (germline CTxcex2, germline Vxcex2 variants); Category 2 (TCR associated molecules; CD3xcex5, CD4, CD7, CD8) and Category 3 (T cell-derived signal transduction molecules; CD3xcex6, p56 type 1, p59 type T. ZAP-70, and SYK) is used, in accordance with the present invention, to identify lymphotropic metastatic potential. As used herein and in the claims, the term xe2x80x9clymphoid gene productsxe2x80x9d is meant to include the lymphoid genes as well as the products thereof.
Accordingly, an object of the invention is to predict the lymphotropic metastatic potential of a solid non-lymphoid tumor.
Another object of the present invention is to provide treatment for such a tumor.
In order to predict the lymphotropic metastatic potential of a solid non-lymphoid tumor, in accordance with the present invention, a plurality of representative samples of the tumor are obtained and the percentage of cells in each of the samples which express lymphoid gene products is determined, wherein the metastatic potential of the tumor is predicted to be low when a low percentage of tumor cells in all of the samples are detected to express lymphoid gene products and predicted to be high when a high percentage of tumor cells in at least one of the samples are detected to express lymphoid gene products.
In order to predict the lymphotropic metastatic potential of a primary solid non-lymphoid tumor, in accordance with the present invention, cells from the tumor are injected sub-cutaneously into at least one anti-AsGMI-treated (NK depleted) nude animal (such as a nude mouse) and the animal examined for tumors at sites other than the site of the injection.
In order to treat a solid non-lymphoid tumor, in accordance with the present invention, a substance comprising a therapeutically effective amount of a molecule linked to a toxin, radionuclide, or chemotherapeutic agent and having binding specificity for a tumor-specific lymphoid gene product idiotype is systemically administered.
The above and other objects, features, and advantages of the present invention will be apparent in the following detailed description of the preferred embodiment thereof when read in conjunction with the accompanying drawings wherein the same reference numerals denote the same or similar parts throughout the several views.